Retention of ball bearing cartridge for turbomachinery

ABSTRACT

An assembly for a turbocharger includes a ball bearing cartridge, a center housing with a bore, a turbine end counterbore and a compressor end surface that includes a recess, and a compressor backplate with an axial extension configured to fit into the recess where the counterbore and the backplate define, at least in part, an axial length of a bearing cartridge chamber. Various other devices, assemblies, etc., are also disclosed.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/323,295, filed Nov. 25, 2008 (now U.S. Pat. No. 7,987,599, issuedAug. 2, 2011), which is a divisional of U.S. patent application Ser. No.11/683,615, filed Mar. 8, 2007 (now U.S. Pat. No. 7,461,979, issued Dec.9, 2008), which is a divisional application of U.S. patent applicationSer. No. 10/879,253, filed Jun. 28, 2004 (now U.S. Pat. No. 7,214,037,issued May 8, 2007). All of the foregoing applications are incorporatedherein by reference.

TECHNICAL FIELD

Subject matter disclosed herein relates generally to turbomachinery forinternal combustion engines and, in particular, rolling element bearingcartridges and bearing housings for such bearing cartridges.

BACKGROUND

The advantages associated with low friction bearings are well known to amultitude of varied industries. High-speed applications with DN (dynamicnumber) values over 1,000,000 are common place for turbomachinery. Thesehigh-speed applications, owing to the fact that rotor imbalance forceincreases as a square function of rotor speed, require damping. Withoutdamping, transmitted forces through the system would cause manywell-known problems such as noise, fretting, loosening of joints, andoverall reduced service life. Further, the bearings themselves wouldhave unacceptable life. For these reasons, turbomachinery bearings arenot hard mounted within their housings. The skilled rotordynamics designengineer spends the majority of his/her life managing these forces,especially those forces encountered as the rotor goes through itsnatural frequencies, commonly referred to as “critical speeds”.

Most turbochargers that employ a low friction rolling element bearinguse two angular contact ball bearings, with each accepting the thrustload in a given axial direction, that are joined together in what iscommonly referred to as a “cartridge”. In a cylindrical coordinatesystem a bearing may be defined with respect to axial, radial andazimuthal dimensions. Within a bearing housing, referred to as housingin subsequent text, a cartridge is located axially and azimuthally viaone or more mechanisms. For proper functioning, some movement can occurin a radial direction along a radial line typically defined by anazimuthal locating mechanism.

Conventional bearing cartridge and housing assemblies typically rely onan axial thrust load pin to locate the cartridge axially and azimuthallywithin a housing. Such pins have a limited ability to align thecartridge in a housing and receive most of the thrust load.Consequently, axial thrust load pins can raise serious wear andmisalignment issues.

Overall, an industry need exists for rolling element bearings and/orhousings that allow for better alignment and/or reduced wear. Variousexemplary bearing cartridges and housings presented herein address suchissues and optionally other issues.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the various methods, devices, systems,arrangements, etc., described herein, and equivalents thereof, may behad by reference to the following detailed description when taken inconjunction with the accompanying drawings wherein:

FIG. 1A is a perspective view diagram of a prior art bearing cartridgefor a turbocharger.

FIG. 1B is a diagram of a prior art bearing cartridge in a prior arthousing.

FIG. 2 is a perspective view diagram of an exemplary bearing cartridgethat does not include an aperture to receive an axial thrust load pin.

FIG. 3 is a side view of an exemplary bearing cartridge that does notinclude an aperture to receive an axial thrust load pin.

FIG. 4 is a cross-sectional view of an exemplary assembly that includesan exemplary housing and an exemplary bearing cartridge.

FIG. 5 is a cross-sectional view of an exemplary housing that includesfeatures for axially locating a bearing cartridge.

FIG. 6 is front view of an exemplary housing assembly that includes aretaining mechanism that acts to axially locate a bearing cartridge inthe housing assembly.

FIG. 7 is a cross-sectional side view of an exemplary retainingmechanism that acts to axially locate a bearing cartridge in a housing.

FIG. 8 is a cross-sectional side view of an exemplary bearing cartridgethat includes various outer surface regions.

FIG. 9A is a cross-sectional side view of an exemplary housing thatincludes two regions with different inner diameters to thereby allow forformation of, for example, two film regions in conjunction with abearing cartridge.

FIG. 9B is a cross-sectional top view of an exemplary housing thatincludes two regions with different inner diameters to thereby allow forformation of, for example, two film regions in conjunction with abearing cartridge.

DETAILED DESCRIPTION

Various exemplary methods, devices, systems, arrangements, etc.,disclosed herein address issues related to technology associated withturbochargers and are optionally suitable for use with electricallyassisted turbochargers.

FIG. 1A shows a perspective view of prior art bearing cartridge 100. Acylindrical coordinate system is shown for reference that includesradial (r), axial (x) and azimuthal (Θ) dimensions. The cartridge 100includes two annular wells 104, 104′ positioned on an outer race 105intermediate a center section 106 and respective ends of the cartridge100. The center section 106 of the cartridge 100 includes an opening 108that cooperates with a pin to position the cartridge 100 axially andazimuthally in a housing or journal. For example, conventional bearingcartridges for turbomachinery often rely on an axial thrust load pinthat is received by such an opening to axially locate the bearingcartridge in a conventional housing.

The wells 104, 104′ are positioned adjacent to outer sections 110, 110′of the outer race 105, respectively. The outer sections 110, 110′ haveequal outer diameters that define a clearance with a housing and therebyallow for formation of lubricant films f, f′.

FIG. 1B shows a cross-sectional view of the prior art cartridge 100 in aprior art housing 160. A pin 162 acts to locate the cartridge 100axially and azimuthally while allowing freedom in the radial direction.In particular, the pin 162 cooperates with the outer race 105. Axialthrust load along the x-axis causes force to be transmitted from theouter race 105 of the bearing cartridge 100 to the housing 160 via thepin 162. As the pin allows for radial movement, some small amount ofclearance exists between the outer diameter of the pin 162 and the innerdiameter of the opening 108. Consequently, during operation thrust maycause axial movement of the cartridge with respect to the housing. Suchmovement can contribute to wear and misalignment.

The pin 162 also allows for lubricant to flow via a conduit in the pin162 to a lubricant entrance well 164 adjacent the center section 106 ofthe cartridge 100. A lubricant exit well 168 exists nearly opposite theentrance well 164 that allows for drainage of lubricant in and about thecartridge 100; noting that an axial position of the pin 162 is offsetfrom an axial position of the lubricant exit well 168 (see dimension Δx)toward a compressor side of the housing 160.

As shown in FIG. 1B, a clearance exists between an outer diameter of theouter sections 110, 110′ and an inner diameter of the housing 160. Inthis prior art assembly, the clearance defines a single film thicknessf. An enlargement of the cross-section shows the single film thickness fas it exists on either side of the well 104. The selection of thisclearance (squeeze film thickness) acts to determine the operationalcharacteristics such as rotor radial freedom and damping of rotorimbalance forces.

FIG. 2 shows a perspective view of an exemplary bearing cartridge 200that does not include an opening for receiving an axial thrust load pin.The cartridge 200 includes two annular wells 204, 204′ positioned on anouter race 205 intermediate a center section 206 and respective ends ofthe cartridge 200. In this example, the cartridge 200 includes openings207 and 207′ that allow jet lubrication to enter and be directed at theballs of the cartridge 200. Additional openings are optionally includedfor lubricant flow.

The wells 204, 204′ are positioned adjacent to end sections 210, 210′,respectively. The end sections 210, 210′ of the outer race 205 haveouter diameters that can define clearances with a housing and therebyallow for formation of lubricant films f1, f1′, which may besubstantially equal.

FIG. 3 shows a side view of an exemplary cartridge 300 such as thecartridge 200 of FIG. 2. The cartridge 300 includes an outer race 305having an approximate length L, an approximate axial midpoint L_(m) andincluding end sections 310, 310′ having outer diameters D_(O) 1, D_(O)1′. In this example, a drain or lubricant opening 309 is positioned atan axial position at or proximate to the midpoint L_(m). The cartridge300 may include openings such as 207, 207′ of the cartridge 200 of FIG.2. The lubricant opening 309 optionally receives a pin or other deviceto limit rotation of the outer race 305. The lubricant opening 309 mayreceive such a rotation limiting device while still being capable ofsome radial movement.

The cartridge 300 includes wells of axial width Δ_(w) 1, Δ_(w) 1′ thatexist between a center section 306 and end sections 310, 310′ with outerdiameters D_(O) 1 and D_(O) 1′. The well widths Δ_(w) 1, Δ_(w) 1′ may besubstantially equal. The outer sections 310, 310′ may differ in axialwidth. For example, the cartridge 300 may include an outer section 310with outer diameter D_(O) 1 that has an axial width less than the outersection 310′ with outer diameter D_(O) 1′.

The exemplary cartridge 300 includes various parameters that may be usedto achieve desired performance characteristics. For example, the axialwidth and outer diameters of the various sections may be used to defineradial clearances/film thicknesses and axial film length(s). In general,judicious selection of thickness, length and number of squeeze films canact to achieve suitable reduction in radial freedom and optimizeddamping of rotor imbalance forces. Various examples capable of multiplesqueeze film thicknesses are described further below with respect toFIG. 8 and FIGS. 9A-B.

FIG. 4 shows a cross-sectional diagram of an exemplary assembly 400 of aturbomachinery device. The assembly 400 includes a bearing cartridge 300positioned in a housing 440 and located axially with aid of a plate 450.In this example, the plate 450 abuts a surface 446 of the housing 440. Apin 460 received by an opening 444 of the housing 440 optionally aids inlocating the cartridge 300 azimuthally with respect to the housing 440.The opening 444 optionally comprises a pin opening having an axis thatintersects the central axis (e.g., x-axis) at an angle φ, which isoptionally non-orthogonal.

In this example, the cartridge 300 is located axially with aid of acounterbore 442 of the housing 440 and the plate 450. In general, theplate 450 and the counterbore 442 define an axial distance that isgreater than the axial length of the outer race of the bearing cartridge300. Proper operation of the assembly 400 requires some amount of radialmovement; consequently, the axially locating mechanism allows thebearing cartridge to move radially. Further, a clearance may be definedby the difference between the axial distance between a surface of theplate 450 and a surface of the counterbore 442 and the axial length ofthe outer race of the bearing cartridge 300. Adjustment to such aclearance may be possible via a fixation mechanism of the plate 450(see, e.g., bolt 452) and/or other features (e.g., gaskets, spacers,etc.). An optional gasket or spacer 459 is shown in FIG. 4.

Various features of the exemplary assembly 400 also act to directlydistribute axial thrust loads to more than one component. For example,the plate 450 can receive thrust loads and the counterbore 442 of thehousing 440 can receive axial thrust loads from the bearing cartridge300. In comparison, the conventional assembly of FIG. 1B transmits axialthrust loads directly and solely to the pin 162. In addition, theexemplary assembly 400 can distribute axial thrust loads over greatersurface area when compared to the pin 162 of the conventional assemblyof FIG. 1B. FIG. 4 also shows a lubricant inlet 441 with a lubricantopening 449 to the entrance well 447 and an inner wall 443 that definesa bore of the housing 440. In comparison to the conventional assembly ofFIG. 1B, the housing 440 of FIG. 4 includes a lubricant entrance well447 (see the lubricant entrance well 164 of FIG. 1B), however, thelubricant inlet 441 thereto, being offset from the opening 444 (seedimension Δx), does not include a pin such as the pin 162 of FIG. 1B.

As already mentioned, the housing 440 includes an opening 444 that canreceive the pin 460 to aid in azimuthal location of the outer race ofthe bearing cartridge 300. Such a pin may be referred to as ananti-rotation pin or an azimuthal locating pin because it acts to locateazimuthally and limit rotation of an outer race of a bearing cartridgewith respect to a housing. In this example, a lubricant drain opening448 of the housing 440 allows for insertion of the pin 460 in theopening 444. In this manner, the lubricant drain opening 448 allowsdrainage of lubricant and insertion and/or adjustment of ananti-rotation pin. While a straight line shows access to the opening444, access is optionally indirect (e.g., not along a straight line).

FIG. 5 shows a cross-sectional top view of an exemplary housing 440 anda plate 450. The exemplary housing 440 includes a proximate recessedsurface 446 and a distal counterbore 442. The proximate recessed surface446 is optionally associated with a compressor side of a turbomachinerydevice and the distal counterbore 442 is optionally associated with aturbine side of a turbomachinery device. Of course, other arrangementsare possible.

The exemplary housing 440 includes an opening 444 set an angle to acentral longitudinal housing axis (e.g., x-axis) that allows forinsertion of a pin. Such a pin may act to azimuthally locate an outerrace of a bearing cartridge in the exemplary housing 440.

The exemplary housing 440 includes an attachment mechanism for the plate450. In this example, threaded holes 445, 445′ are providing that openalong the surface 446. The holes 445, 445′ receive bolts 452, 452′,respectively. Washers 453, 453′ are also shown in this example. Otherattachment mechanisms may be used for attaching a plate or limitingmechanism to a housing. Further, while a substantially circular shapedplate is shown, other shapes or limiting mechanisms are possible and mayinclude one or more surfaces and/or one or more components that act tolimit movement of an outer race of a bearing cartridge in thecylindrical bore of a housing in conjunction with a counterbore. Anexemplary housing optionally includes an attachment mechanism ormechanisms for one or more limiting components that extend radiallyinward to a minimum radius less than the inner radius of a cylindricalbore wherein at least some of the components can act to limit axialmovement of a bearing cartridge in the cylindrical bore.

FIG. 6 shows a front view of an exemplary assembly 600 that includes anexemplary housing 440 and an exemplary plate 450. In this example, theplate 450 fits in a recess of the housing 440. The plate 450 acts todefine an axial distance along with a counterbore of the housing (notshown in FIG. 6, see, e.g., FIG. 5). In conjunction with an axial lengthof an outer race of a bearing cartridge, the axial distance acts todefine a clearance or clearances between the outer race and the plate450 and/or the counterbore of the housing 440. The exemplary plate 450includes four openings 454, 454′, 454″, 454′″ for use in securing theplate 450 to the housing 440. A bolt 452 or other device passes throughthe opening 454′″ to secure the plate 450 to the housing 440. In thisexample, a washer 453 cooperates with the bolt 452 to secure the plate450.

The plate 450 includes an opening 456 that has an inner diameter lessthan the inner diameter of a substantially cylindrical bore of thehousing 440. In this example, the opening 456 is substantially coaxialwith the cylindrical bore of the housing 440. A counterbore 442 of thehousing 440 has an inner diameter less than the inner diameter of thecylindrical bore of the housing 440. In this example, the counterbore442 has an arc length less than 360 degrees. Exemplary counterbores mayinclude one or more arc segments, protrusions, etc., that extendinwardly toward a longitudinal or center axis of the cylindrical bore tothereby limit movement of an outer race of a bearing cartridge in thecylindrical bore.

FIG. 7 shows an exemplary assembly 700 that includes an exemplary plate750 and a component 782 that includes channels (e.g., for seating sealrings to form a seal between the component 782 and the plate 750). Inthis example, the plate 750 is a compressor backplate that fits into therecessed region of a housing 440, for example, at a surface 446. In thisexample, an attachment mechanism includes use of blots 752, 752′ tosecure the plate 750 to the housing 440. The plate 750 extends radiallyinward past the surface 446 where it further extends past at least aportion of an outer race 305 of a bearing cartridge. The plate 750includes an opening that has an inner dimension (e.g., a diameter, etc.)that is less than the outer diameter of the outer race 305. While anexemplary plate may include a substantially circular opening with adiameter less than that of an outer race of a bearing cartridge, variousexemplary plates may include other shapes, protrusions, etc., thatextend inwardly past an inner diameter of a substantially cylindricalbore of a housing to thereby limit axial movement of an outer race of abearing cartridge. For example, an exemplary plate optionally includesone or more protrusions that extend radially inward toward a centralaxis to limit movement of an outer race of a bearing cartridge. Whilenot shown in FIG. 7, the housing 440 optionally includes a counterboreto limit movement of the outer race 305, for example, where the plate750 is positioned at a proximate end of a substantially cylindrical boreof a housing and the counterbore is positioned at distal end of thesubstantially cylindrical bore of the housing (see, e.g., thecounterbore 442 of FIG. 5). Further, the housing 440 of FIG. 7optionally includes an opening such as the opening 444 of FIG. 5 (e.g.,a pin opening, etc.). While such an opening is sometimes referred toherein as a “pin” opening, the term pin may optionally refer to variousmechanisms such as screws, bolts, etc., that act to limit rotation of anouter race of a bearing cartridge.

As shown in FIG. 7, the assembly 700 includes a collar 782, having anaxial length Δx_(c), that abuts the inner race and that extends axiallyinto an opening of the plate 750.

FIG. 8 shows a cross-sectional diagram of an exemplary bearing cartridge800 that allows for multiple films of optionally different thicknesses.The cartridge 800 includes a center section 806, intermediate sections810, 810′ and outer sections 812, 812′. The bearing also includeslubricant passages 807, 807′ and 809.

An enlargement shows various wells (e.g., wells, grind reliefs, etc.)and/or transitions from a first outer diameter to a second outerdiameter. A wall 866 of a housing or journal having an inner diameteracts to define clearances and film thicknesses f1, f2. In a firstscenario 801, wells have curvilinear cross-section; in a second scenario802, wells have substantially polygonal cross-section; and in a thirdscenario 803, a step in outer diameter exists between a thick filmregion f1 and a thinner film region f2. The scenarios 801, 802, 803 areexemplary as others may be used to create clearances that form multiplefilm thicknesses.

A housing or journal may act to define clearances that form multiplefilm thicknesses between the housing and one or more outer diameters ofa bearing cartridge. For example, an exemplary housing may include twoor more inner diameters that act to define more than one annularclearance with a bearing cartridge and a counterbore to help axiallylocate the bearing cartridge and/or an opening for receiving a pin tohelp azimuthally locate an outer race of the bearing cartridge.

FIG. 9A shows a cross-sectional, side view of an exemplary housing 940and FIG. 9B shows a cross-sectional top view of the exemplary bearinghousing 940. The exemplary housing 940 can house a bearing cartridge andact to define clearances between an outer surface of the bearingcartridge and an inner wall of the housing 940 wherein the clearancesact to form various films that can be aimed at reduction of unwantedexcessive radial clearance and/or optimized damping of rotor imbalanceforces.

The exemplary housing 940 includes a counterbore 942, an opening 944, alubricant opening 945, and a surface 946 substantially perpendicular toa central axis (e.g., x-axis). The opening 944 optionally comprises apin opening having an axis that intersects the central axis at an angleφ, which is optionally non-orthogonal. The surface 946 and thecounterbore 942 may define a distance that in combination with a bearingcartridge acts to define an axial clearance. A plate (see, e.g., theplate 450 of FIG. 6) or other component optionally cooperates with thesurface 946 to define a proximate end of a bearing cartridge chamberwhile the counterbore 942 defines a distal end of the bearing cartridgechamber.

The bearing cartridge chamber includes an inner surface 966 that has afirst inner diameter and an inner surface 967 that has a second innerdiameter wherein the first inner diameter exceeds the second innerdiameter. A bearing cartridge that includes an outer surface having anouter diameter may act to define annular clearances with the first andsecond inner surfaces 966, 967 when positioned in the housing to form anassembly.

Various exemplary devices, methods, systems, arrangements, etc.,described herein pertain to formation and use of multiple filmthicknesses. In various examples, one film has damping characteristicsand another film has characteristics that minimize excessive radialfreedom and play.

An exemplary bearing cartridge includes an inner film to outer filmratio of approximately 1:2, i.e., the inner film being approximatelytwice the thickness of the outer film. For example, an inner film ofapproximately 0.0030 inch (approx. 0.076 mm) and an outer film ofapproximately 0.0015 inch (approx. 0.0038 mm) wherein the inner filmacts to dampen vibrations and the outer film acts to limit rotor radialplay. Such an exemplary bearing cartridge may be suitable for use in acommercially available GARRETT® GTA47-55R turbomachinery device(Torrance, Calif.).

In general, a sufficiently thick film can act to reduce noise andvibration and loading through the system; whereas a thinner film canreduce slop or play in the system (e.g., rotor play, etc.). A thinnerfilm may also allow for reduction in wheel to housing clearances in aturbocharger system, which can act to reduce undesirable secondaryaerodynamic flows that would cause reduced compressor and turbine stagethermodynamic efficiencies.

Various examples include one or more thinner clearance regions proximateto an outer end(s) of a bearing cartridge. A pair of thinner clearanceregions proximate to outer ends of a bearing cartridge may limit pivotwhen compared to a thinner clearance region(s) positioned proximate toor at a center section.

Although some exemplary methods, devices, systems arrangements, etc.,have been illustrated in the accompanying Drawings and described in theforegoing Detailed Description, it will be understood that the exemplaryembodiments disclosed are not limiting, but are capable of numerousrearrangements, modifications and substitutions without departing fromthe spirit set forth and defined by the following claims.

The invention claimed is:
 1. An assembly for a turbocharger, theassembly comprising: a ball bearing cartridge that comprises two sets ofrolling elements and an outer race wherein the outer race comprises acenter section surface having a center section diameter, twointermediate section surfaces having an intermediate section diameterand two outer section surfaces having an outer section diameter, thesections disposed along an axial length defined by two opposing ends ofthe outer race, step transitions, each of the step transitionspositioned between a respective one of the outer section surfaces and arespective one of the intermediate section surfaces, and two wells, eachof the wells positioned between the center section surface and arespective one of the intermediate section surfaces, wherein each of thewells comprises a lubricant channel to direct lubricant to a respectiveset of the two sets of rolling elements; a center housing that comprisesa lubricant inlet, an inner wall that defines a bore wherein the innerwall comprises a lubricant opening to receive lubricant from thelubricant inlet, a first inner surface having a first inner diameter,and a second inner surface having a second inner diameter wherein thefirst inner diameter exceeds the second inner diameter, a turbine endcounterbore having a counterbore inner diameter wherein the sectiondiameters of the outer race exceed the counterbore inner diameter, and acompressor end surface that comprises a recess; and a compressorbackplate that comprises an axial extension configured to fit into therecess wherein the axial extension comprises an opening having an innerdiameter less than the section diameters of the outer race; wherein thecounterbore and the backplate define an axial length of a bearingcartridge chamber wherein the axial length of the chamber exceeds theaxial length of the outer race to provide clearance between the outerrace and the chamber.
 2. The assembly of claim 1 further comprising afeature to adjust clearance between the outer race and the chamber, thefeature being disposed between the backplate and the housing.
 3. Theassembly of claim 2 wherein the feature comprises a gasket.
 4. Theassembly of claim 2 wherein the feature comprises a spacer.
 5. Theassembly of claim 1 wherein the outer race of the ball bearing cartridgecomprises an opening for drainage of lubricant.
 6. The assembly of claim1 wherein the outer race of the ball bearing cartridge comprises anopening for receipt of a locating pin.
 7. An assembly comprising: aturbocharger center housing that comprises a lubricant inlet, an innerwall that defines a bore having an axis extending from a compressor sideto a turbine side of the housing wherein the inner wall comprises,positioned in an axial direction toward the compressor side, a lubricantopening to receive lubricant from the lubricant inlet, a first innersurface having a first inner diameter, and a second inner surface havinga second inner diameter wherein the first inner diameter exceeds thesecond inner diameter, a turbine end counterbore having a counterboreinner diameter wherein the first inner diameter and the second innerdiameter of the bore defined by the inner wall exceed the counterboreinner diameter, and a compressor end surface that comprises a recess;and a compressor backplate that comprises an axial extension configuredto fit into the recess wherein the axial extension comprises an openinghaving an inner dimension wherein the first inner diameter and thesecond inner diameter of the bore defined by the inner wall exceed theinner dimension of the axial extension; wherein the counterbore and thebackplate define, at least in part, an axial length of a bearingcartridge chamber.
 8. The assembly of claim 7 further comprising afeature to adjust the axial length of the bearing cartridge chamber, thefeature being disposed between the backplate and the housing.
 9. Theassembly of claim 8 wherein the feature comprises a gasket.
 10. Theassembly of claim 8 wherein the feature comprises a spacer.